Technical Field
The present disclosure relates to a data access apparatus, and more particularly, to a data access apparatus using a memory device, capable of allowing 16-bit or more data to be easily read/written using one 8-bit memory device.
Description of the Related Art
In general, a CPU (central processing unit), which executes the overall control of an electronic control system, performs an access process of reading or writing data from or to a memory device as a storage device.
That is, the access process of reading/writing data from/to the memory device is mainly performed by the CPU. Accordingly, the read or write operation means that reading or writing is performed on the basis of the CPU. The read operation refers to bringing data in the memory device to the CPU, and the write operation refers to transmit data from the CPU to the memory device.
Meanwhile, a solar inverter system, which has been recently spotlighted from among electronic control system, is a system which generates electricity by converting DC energy supplied from a solar module into AC energy.
When the solar inverter system is operated, a variety of types of information such as a voltage, a current, and an amount of power generation are stored in a memory device and the information stored in the memory device is stored in external devices (e.g. a monitoring device) through communication.
The amount of power generation in the solar inverter system is very important data, and the cumulative amount of power generation (i.e. the total amount of power generation to date from when electricity is generated by the solar inverter system) is very important information for a user.
Meanwhile, existing 8-bit and 16-bit memory devices may maximally record 256 and 65,536 data words, respectively. These capacities of the memory devices are too small to display the cumulative amount of power generation in megawatts. Thus, at least 24-bit memory device (which maximally records 16,777,216 data words) must be used to display the cumulative amount of power generation in megawatts. Therefore, there is a need for the method of storing 24-bit data in the commercial 8-bit memory device.
Due to the recent development of communication methods and devices, the amount of data, which may be transferred to the external device of the solar inverter system at a time, is increased as in data of 8 bits, 16 bits, or 24 bits. In addition, the amount of data transferred to the user through communication is gradually increased. Nevertheless, there is no occurrence of deterioration of communication speed.
However, 8-bit memory devices (particularly, nonvolatile memory devices) are mainly used to store data exchanged through communication, and 24-bit memory devices are expensive.
In addition, since the commercial 8-bit memory device must be used when important data is read/written from/in the memory device in the solar inverter system, the volume of data is limited to 8 bits. In addition, a 24-bit memory device must be purchased in the market in order for 24-bit data to be read/written, but the 24-bit memory device is expensive.
The 8-bit memory device (the commercial memory devices) is mainly used in the solar inverter system. The 8-bit memory device is generally used and cheap.
When important data (e.g. a cumulative amount of power generation) of the solar inverter system is stored using the commercial 8-bit memory device, only 8-bit data may be stored due to the limited capacity (8 bits) of the memory device.